1. Field of the Invention
The present invention relates to an apparatus for measuring optoelectric properties and measurement method thereof. More particularly, the present invention relates to an apparatus for measuring optoelectric properties of an organic light-emitting device (OLED) and the measurement method thereof.
2. Description of the Related Art
Organic light-emitting device (OLED) is a flat panel display device with a high electrical-to-photonic energy conversion efficiency. OLED display panels are frequently used in mobile phones, personal digital assistants (PDAs) and various other types of flat display devices. Because of the many special properties useful in this multi-media age including no viewing angle restriction, easy to fabricate, low production cost, high response speed, wide operating temperature range and full colorization, research and development on OLEDs are intense and focused. The organic light-emitting panel is a device that utilizes the organic functional materials, which radiate spontaneously to achieve image display. According to the molecular weight of the organic functional materials, the organic light-emitting panel is classified into two types, i.e. the small molecule OLED (SM-OLED) and the polymer light-emitting device (PLED).
In general, optoelectric properties of OLED must be tested as soon as the fabrication is finished. In other words, the brightness, the coloration, the viewing angle, the degree of display uniformity, the contrast and the response time must be measured accurately. Conventionally, the optoelectric properties of an OLED are measured according to the following method.
First, an organic light-emitting device (OLED) is clamped on a simple fixture. Thereafter, power is provided to the OLED through a power supply such as a Topmard 6306D direct current power supply. A photo-detector (SR-2) is positioned manually before a brightness measurement of the OLED is carried out. The resulting measurement is recorded manually and then fed into a computer for data rearrangement, graph plotting or statistical data analysis. A viewing angle measurement of the OLED is then carried out manually by turning the fixture holding the OLED a fixed rotation angle (for example, a rotation of 10°). Subsequently, the aforementioned photo-detector is again used to measure the brightness. A measurement is carried out for each 10° rotation. Furthermore, uniformity of the OLED is also carried out manually by moving the fixture holding the OLED to a new position and then using naked-eye inspection and the aforementioned photo-detector to measure the brightness. To measure the contrast of the OLED, a brightness meter (Lux meter) is used to measure overall brightness level of the surrounding. Thereafter, the brightness meter is used to find the contrast ratio of the OLED. After the measurement of various optoelectric properties, all the data have to be fed into a computer manually so that the data can be processed, plotted out in graphic form or statistically analyzed. Furthermore, the aforementioned measurements may have to be repeated a number of times during which the operator cannot leave if an accurate and useful analysis is required.
Hence, in the conventional method of measuring the optoelectric properties of an OLED, a lot of time and labor is spent during the measurement to adjust the angles, position the device, clamp the device, align the instrument, dissemble the device and calibrate the instruments. Each OLED has to go through the same set of operations manually. Furthermore, visual alignment is very imprecise and the manual adjustment, setting, positioning and turning of the OLED and the measuring instrument may produce so much errors that the measured results are highly inaccurate. Lastly, the conventional method does not provide any means of gauging the response time of the OLED.